Plaster board



May 11 1926.

J. SCHUMACHER PLASTER BOARD Filed Nov. 14, 1921 [7L Mentor.

Patented May 11, 1926.

UNITED STATES insane I JOHN SGHU'MAGHER, OF LOS ANGELES, CALIFORNIA.

PnAs'rnn BoAnn.

I Application filed November 14, 1921. Serial No. 514,914.

This invention relates to a plaster board formed of a plaster core and covering sheets. Such boards are commonly used for covering walls in building constructions.

It is the primary object of this invention to provide a board which is reinforced at the edges, and with the covering sheets so arranged that they are securely attached to the plaster core at their edges, thereby pre- 1 venting the sheets from being accidentally pulled away from the plaster in handling It is another object of this invention to provide a board so reinforced at its edges, that it will not chip.

Other objects and corresponding accomplishments will be apparent from the sub joined specification and drawing accompanying the specification, in which z.

Fig. 1 is one type of board embodying my invention shown in perspective; and Fig.

2 is a still further modified form.

Referring particularly to Fig. 1, a board is shown comprising a plaster core 19 be- 'tween covering sheets 20 and 22. I prefer to use a moist unstable plastic substance, which may be fed between continuously ad vancing sheets of paper. The side edges of the paper sheets are turned inwardly and the product in its soft condition is cut into initial lengths. In setting and drying, the paper adheres to the plaster core 19.

In Fig. 1, the edges of the paper are shown forming return bends with rectangular corners and the free edges of the upper and lower sheets adjacent one another. The side edges are in efi'ect completely covered forming a finished edge so thattrimming is not necessary.. The edges of the paper are embedded in the plaster core and form. a reinforcement which strengthens the board. The edge of the board is covered by a tough sheet preventing chipping. Furthermore, there is no opportunity for the board to start peeling at the edge, as the edge of the paper is embedded in theplaster.

In Fig. 1 the invention is shown embodied in a board having rabbeted edges provided with extensions which may be lapped. In effect the ends'of the board are halved. The construction is obtained by turning one end of one cover inwardly short of the other. It

is obvious that it is iunnaterial whether the sheets are parallolto each other in the core, or whether they enter the core at angles. However, with the construction shown in Fig. 1 the sheet should be bent to form halves which will interlock and form. smooth joints. Fig. 2 shows a construction similar to Fig. 11, but the edges are bent to form bevelled dove-tails. Thus, a board will have to one edge in the form of a bevelled recessto receive the tongue.

What I claim is:

1. A plaster boardcomprising a body of plaster composition having rabbeted edges, paper attached to and covering both sides of the main body and one side of each of the rabbeted edges, and paper covering the opposite sides of each of said rabbeted edges and embedded in the body of plaster coinposition, substantially as described.

2. A plaster board comprising a body of plaster composition having a tongue at a side edge to form an interlocking joint with the complementary edge of an adjacent board, each face. of said body having an adhering cover sheet of fiberous material, one of said cover sheets being extended over said tongue and embedded in the body of the plaster composition.

3. A plasterboard comprising a body of plaster composition having a stepped or rabbeted edge, each face of said bodyhaving acovering of fibrous material, one of said coverings being folded to enclose the extended portion of said rabbeted edge-and being embedded in the body of the plaster composition.

4:. A plaster board comprising a body of plaster composition having an extension at each side edge to form an interlocking joint with the corresponding edge of an adjacent board, each face of said body having an adhering cover sheet of fibrous material, one of said cover sheets being folded around the adjacent extension and extended inward- 1y a distance into the body of plaster composition.

In witness that I claim the foregoing I have hereunto subscribed my name this 8th day of. November, 1921.

JOHN SCHUMACI-IER. 

